河原 創

J-GLOBALへ         更新日: 14/07/30 22:28
 
アバター
研究者氏名
河原 創
eメール
kawaharaeps.s.u-tokyo.ac.jp
URL
http://www-sys.eps.s.u-tokyo.ac.jp/~kawahara/index_ja.html
所属
東京大学
部署
理学系研究科・地球惑星科学専攻
職名
助教
学位
理学博士 (東京大学)
科研費研究者番号
90649758

プロフィール

太陽系外惑星の惑星科学や宇宙生物学をめざした新しい観測手法の構築や生命の痕跡の探査などに関心を持っています。過去には銀河団・大規模構造の物理とその宇宙論的応用などの研究もしていました。

研究分野

 
 
  • 天文学 / 天文学 / 太陽系外惑星
  • 天文学 / 天文学 / 宇宙生物学
  • 天文学 / 天文学 / 観測的宇宙論

受賞

 
2012年1月
Aspen center for physics Martin and Beate Block Award
 

論文

 
Hajime Kawahara, Naoshi Murakami, Taro Matsuo, Takayuki Kotani
The Astrophysical Journal Supplement Series   212, 27   2014年5月   [査読有り]
We propose the application of coronagraphic techniques to the spectroscopic
direct detection of exoplanets via the Doppler shift of planetary molecular
lines. Even for an unresolved close-in planetary system, we show that the
combination of a visi...
Mitsuishi I, Kawahara H, Sekiya N, Sasaki S, Sousbie T, Yamasaki N.
The Astrophysical Journal   783(2) 137   2014年3月   [査読有り]
Hajime Kawahara, Teruyuki Hirano, Kenji Kurosaki, Yuichi Ito, Masahiro Ikoma
accepted by ApJL      2013年9月   [査読有り]
Hajime Kawahara, Taro Matsuo, Michihiro Takami, Yuka Fujii, Takayuki Kotani, Naoshi Murakami, Motohide Tamura, Olivier Guyon
Astrophysical Journal   758(1) 13   2012年10月   [査読有り]
The oxygen absorption line imprinted in the scattered light from the Earth- like planets has been considered the most promising metabolic biomarker of the exo-life. We examine the feasibility of the detection of the 1.27 μm oxygen band from habita...
Hiroki Akamatsu, Hajime Kawahara
Accepted by PASJ      2012年9月   [査読有り]
We perform a systematic X-ray analysis of six giant radio relics of four
clusters with Suzaku satellite by compiling new analysis of CIZA 2242.8-5301,
Zwcl 2341.1-0000, and Abell 3667 and previous results of A3667 and A3376.
Especially we first ob...
Hajime Kawahara
ApJ Letters   760(1) L13   2012年11月   [査読有り]
Yuka Fujii, Hajime Kawahara
Astrophysical Journal   755 101   2012年8月   [査読有り]
Aiming at obtaining detailed information of surface environment of
Earth-analogs, Kawahara & Fujii 2011 proposed an inversion technique of annual
scattered light curves named the spin-orbit tomography (SOT), which enables one
to sketch a 2-dimensi...
Mark Swain, Pieter Deroo, Giovanna Tinetti, Morgan Hollis, Marcell Tessenyi, Michael Line, Hajime Kawahara, Yuka Fujii, Adam Showman, Sergey Yurchenko
   2012年5月
We report near-infrared measurements of the terminator region transmission
spectrum and dayside emission spectrum of the exoplanet WASP-12b obtained using
the HST WFC3 instrument. The disk-average dayside brightness temperature
averages about 2900...
Hajime Kawahara, Yuka Fujii
ApJ Letters   739(2) L62   2011年9月   [査読有り]
We develop an inversion technique of annual scattered light curves to sketch a two-dimensional albedo map of exoplanets in face-on orbits. As a test bed for future observations of extrasolar terrestrial planets, we apply this mapping technique to ...
Yuka Fujii, Hajime Kawahara, Yasushi Suto, Satoru Fukuda, Teruyuki Nakajima, Timothy A. Livengood, Edwin L. Turner
ApJ   738 184   2011年8月   [査読有り]
As a test-bed for future investigations of directly imaged terrestrial
exoplanets, we present the recovery of the surface components of the Earth from
multi-band diurnal light curves obtained with the EPOXI spacecraft. We find
that the presence an...
Thierry Sousbie, Christophe Pichon, Hajime Kawahara
MNRAS   414(1) 384-403   2011年6月   [査読有り]
The recently introduced discrete persistent structure extractor (DisPerSE,
Soubie 2010, paper I) is implemented on realistic 3D cosmological simulations
and observed redshift catalogues (SDSS); it is found that DisPerSE traces
equally well the obs...
Yoh Takei, Eugenio Ursino, Enzo Branchini, Takaya Ohashi, Hajime Kawahara, Kazuhisa Mitsuda, Luigi Piro, Alessandra Corsi, Lorenzo Amati, Jan-Willem den Herder, Massimiliano Galeazzi, Jelle Kaastra, Lauro Moscardini, Fabrizio Nicastro, Frits Paerels, Mauro Roncarelli, Matteo Viel
ApJ   734(2) 91   2011年6月   [査読有り]
We assess the possibility to detect the warm-hot intergalactic medium (WHIM)
in emission and to characterize its physical conditions and spatial
distribution through spatially resolved X-ray spectroscopy, in the framework of
the recently proposed ...
Hajime Kawahara, Hiroshi Yoshitake, Takahiro Nishimichi, Thierry Sousbie
ApJ Letters   727 L38   2011年1月   [査読有り]
We report on a new merging group of galaxies, Suzaku J1552+2739 at z ~ 0.08
revealed by a SUZAKU observation. The group was found by observing a junction
of galaxy filaments optically identified in the Sloan Digital Sky Survey
spectroscopic data. ...
Hajime Kawahara, Yuka Fujii
ApJ   720(2,Pt.1) 1333-1350   2010年8月   [査読有り]
Scattered lights from terrestrial exoplanets provide valuable information
about the planetary surface. Applying the surface reconstruction method
proposed by Fujii et al. (2010) to both diurnal and annual variations of the
scattered light, we deve...
Hajime Kawahara
ApJ   719(2,Pt.1) 1926-1931   2010年8月   [査読有り]
We derive the axis ratio distribution of X-ray clusters using the XMM-Newton
catalogue (Snowden et al. 2008). By fitting the contour lines of the X-ray
image by ellipses, we confirm the X-ray distribution is well approximated by
the elliptic distr...
Erik D. Reese, Hajime Kawahara, Tetsu Kitayama, Naomi Ota, Shin Sasaki, Yasushi Suto
ApJ   721(1,Pt.1) 653-669   2010年8月   [査読有り]
We perform a uniform, systematic analysis of a sample of 38 X-ray galaxy
clusters with three different Chandra calibrations. The temperatures change
systematically between calibrations. Cluster temperatures change on average by
roughly ~6% for the...
Y. Fujii, H. Kawahara, Y. Suto, A. Taruya, S. Fukuda, T. Nakajima, E. L. Turner
ApJ   715(2,Pt.1) 866-880   2010年6月   [査読有り]
Characterizing the surfaces of rocky exoplanets via the scattered light will
be an essential challenge to investigate the existence of life on habitable
exoplanets. We present a simple reconstruction method for fractional areas of
different surfac...
Hajime Kawahara, Erik D. Reese, Tetsu Kitayama, Shin Sasaki, Yasushi Suto
ApJ   687(2) 936-950   2008年11月   [査読有り]
Our previous analysis indicates that small-scale fluctuations in the
intracluster medium (ICM) from cosmological hydrodynamic simulations follow the
lognormal distribution. In order to test the lognormal nature of the ICM
directly against X-ray ob...
Hajime Kawahara, Tetsu Kitayama, Shin Sasaki, Yasushi Suto
ApJ   674(1) 11-21   2008年2月   [査読有り]
The Hubble constant estimated from the combined analysis of the
Sunyaev-Zel'dovich effect and X-ray observations of galaxy clusters is
systematically lower than those from other methods by 10-15 percent. We examine
the origin of the systematic und...
Hajime Kawahara, Yasushi Suto, Tetsu Kitayama, Shin Sasaki, Mamoru Shimizu, Elena Rasia, Klaus Dolag
ApJ   659(1) 257-266   2007年4月   [査読有り]
The origin of the recently reported systematic bias in the spectroscopic
temperature of galaxy clusters is investigated using cosmological
hydrodynamical simulations. We find that the local inhomogeneities of the gas
temperature and density, after...

経歴

 
2012年11月
   
 
東京大学 理学系研究科地球惑星科学専攻 助教
 
2010年4月
 - 
2012年10月
学術振興会特別研究員 (首都大)
 
2009年4月
 - 
2010年3月
学術振興会特別研究員 (東京大学)
 

Misc

 
太陽系外惑星をCTスキャンする
河原 創、藤井友香
日本物理学会誌   68(1) 4   2013年1月
ゆらぐ銀河団ガスと宇宙論
河原 創
天文月報   102(10) 546-555   2009年10月

競争的資金等の研究課題

 
文部科学省: 科学研究費補助金(若手研究(B))
研究期間: 2013年 - 2016年    代表者: 河原 創